Inside the Forbidden City (1965)

It seems that Li Zhenfei was once an imperial concubine, who often found herself competing with her rival Madame Liu for the emperor's sole, undivided attention. When Li gives birth to the Emperor's child, the jealous Liu switches the boy with a cat and commands a servant named Kou Zhu to kill the baby. However, Kou Zhu ignores the order and gives the prince-to-be to the emperor's brother, a decision which eventually leads to the boy being adopted by the emperor himself! But as fate would have it, to go along with his new son, the emperor has a new wife as well - Madame Liu! As this strange new family unit is being constructed, poor Li Zhenfei has been confined to the forbidden palace, condemned to never see or speak to her son, the prince. But destiny reunites her with her son, but will this family reunion be a happy one? And will Madame Liu finally be punished for her treachery?